Sizing of textile materials



Patented June 10, 1941 I srzmo' on 2,244,704 y rsx'mn mumps Merlin Martin Brubaker, Lindemerc, Del, assign- -or' to E. 1. du Pont de Nemoura &- Company,

Wilmington, Del., a corporation of Delaware No Drawing. Application August 30, 1937, Serial No. 161,878

4 Claims.

This invention relates to the sizing of textile materials, and more particularly to a novel class of water-soluble sizing agents, and the process of applying the same.

In the modern high-speed weaving of fabrics it is necessary to protect the warp threads with ment which increases its strength and wear resistance, partially due, no doubt, to its lubricating effect. Heretofore, starch, gelatin, glue, and casein have been most extensively used for sizing yarns. All of these agents, however, have been found to be not satisfactory for. one or more reasons. Thus, it is necessary when using these materials, to add sulfonated oils, glycerin, or other softening agents so that the resulting yam will be supple and flexible and not harsh and stiff. Large quantities of these materials are required to give suflicient protection. They lack uniformity; gelatin especially, which is made by partial hydrolysis of certain animal tissues of varying physical and chemical properties depending on the genus or specie of animal from which the tissues were taken, shows a lack of uniformity from shipment to shipment. But the most serious objection is the dimculty with which these sizing agents are removed from fabric. To remove starch, for example, the practice is to solubilize the starch with costly enzymes, which must be applied under carefully controlled conditions. Gelatin tends to insolubilize with age and is also difficult to remove even with vigorous scouring. Incomplete removal of these sizing agents results in non-uniformity which is especially marked in the dyed fabrics.

It is an object of this invention to overcome the aforementioned defects and other resultant and related defects. A further object is the produc-' I have found that water-soluble salts of certain polycarboxylic acids, heretofore unknown, are particularly suitable for sizing rayon and cotton yarns. These polycarboxylic acids may be defined as interpolymers of methacrylic acid and an alkyl methacrylate.

These materials, which are resinous, are made from low molecular weight materials of definite chemical composition, the purity of which can be accurately controlled and checked. Thus, methacrylic acid has the following structure:

CHI-(3000B C and methyl methacrylate is the methyl ester of this acid.

Methacrylic acid boils at 71 C. at 20 mm. of

mercury pressure or at 122 C. at 100 mm., while methyl methacrylate boils at 100 C. at 760 mm.'

Each of these materials can, therefore, be purifled by simple distillation before they are interpolymerized to form the resins which are the subject of this patent application. This assures a uniform product since the proportion of each constituent can be accurately controlled by weighing and since other factors such as catalyst, temperature, and time are also readily controlled. Any of the materials covered in this invention can easily be reproduced. This fact will be more obvious from the description of the methods of preparation of these materials which is given below.

Either in the form of dry solids or as aqueous solutions these interpolymers are immune to bacterial growth and can be stored indefinitely without harmful results. They are also stable to temperatures of 100 C. or higher, and are stable to acids or alkalis. These interpolymers are soluble in water in the form of their salts and are precipitated by the addition of an acid. At higher temperatures hydrolysis or saponiiication takes place in the presence of acid or excess alkali.

The invention is best illustrated by the following examples in which parts are by weight.

EXAMPLE I (A) Preparation of resin Seventy-five (75) parts of alpha-methacrylic acid (hereafter referred to simply as methacrylic acid), 25 parts of they methyl ester of alpha-methacr'ylic acid (hereafter referred to as methyl methacrylate) and 1 part of benzoyl peroxide were dissolved in 500 parts of toluene and heated in a flask with a reflux condenser for twelve hours at the boiling point. Interpol'ymerization oi methacrylic acid and methyl methacrylate occurred and the interpolymer separated as a finely divided white powder having an acid number of 489.

(B) Preparation of the solution One hundred (100), parts of this powder were stirred into a solution containing about 600 parts of water and 30 parts of sodium hydroxide. Steam was then bubbled into this mixture with rapid stirring. As the material approached the boiling point it dissolved readily. Additional sodium hydroxide was added from time to time to keep the solution slightly alkaline. A total of almost 35 parts of caustic was required. When all the resin had dissolved, additional water was added to give a total of 1000 parts of solution. This solution thus contained of the interpolymer, calculated as the free acid.

(6') Application of the resin to yarn One hundred (100) parts of the solution described above was further diluted with water to give 1000 parts of a l solution of the resin. This solution was used to size a beam of 150 denier 40-filament viscose rayon yarn. The beam contained 8700 ends and was 845 yards in length. The size was applied on an ordinary rayon slashing machine. The sized yarn was flexible and soft as compared to the same yarn sized with a solution containing 42 pounds of gelatin and 2.5 pounds of sulfonated oil in 110 gallons of water which was used as a control. When a thread was broken by direct tension, the filaments separated only very slightly at the ends formed by the break. When drawn between thumb nail and finger with slight pressure applied, the yarn showed little tendency to separate into the individual filaments. These are tests that are commonly used by those skilled in the art to ,determine if a yarn has satisfactory weaving properties and the tests indicated that this yarn would weave satisfactorily. The warp was used in a five harness loom to weave a high-count satin fabric having 230 warp thread per inch.

No difliculties, such as fiuffing and breaking of the warp threads, were encountered during the weaving and in this respect this yarn was superior to the gelatin sized yarn with which considerable fiufilng and occasional breaking of the threads occurred.

The fabric obtained from this yarn was soft and flexible as compared to that made with gelatin size. A sample of this fabric was dyed with direct dyes without previous scouring. The dye was absorbed uniformly and the finished fabric was equal in every respect to a similar fabric woven from gelatin-sized yarn and thoroughly scoured before dyeing.

EXAMPLE II (.4) Preparation of resin Fifty (50) parts of methacrylic acid, 50 parts of methyl methacrylate and 1 part of benzoyl peroxide were dissolved in toluene and heated to interpolymerize the methacrylic acid and methyl methacrylate. A finely divided powder separated. The acid number of this powder was 320.

(B) Preparation of solution A 10% solution of this resin was prepared by the method described above, except that only 23 parts of sodium hydroxide were used,

(0) Application of resin to yarn Three (3) pounds of the solution described above was diluted to 10 gallons of solution and used to size skeins of 200 denier 'lfi-filament viscose rayon yarn at a temperature of F. The excess solution was removed by centrifugingand the skeins were dried by passing them slowly through a tunnel oven at to 180 F. At the end of the-drying operation the yarn contained about 7% moisture. The skeins were then placed on reels and wound onto spools. These spools were placed on vertical spindles and rotated at 9400 R. P. M. while the yarn was wound oif onto new spools at such a rate that it received a twist of 55 turns per inch. Some of the yarn was thus twisted to the right and some to the left, the yarn being intended for use as filling thread in crepe fabrics. After the twisting operation the spools of yarn were placed in steaming ovens and steamed for one hour at about F. This steaming softened the size so that when the yarn was cooled and dried the twist was set and the yarn would not readily untwist when wound off the spools. This yarn was then wound onto bobbins and used as filling thread in weaving a fabric having an acetate warp. In this fabric the filling contained four righthand twisted EXAMPLE III (A) Preparation of resin Twenty-five (25) parts of methacrylic acid and 75 parts of methyl methacrylate were interpolymerized by heating in toluene with 1 part of benzoyl peroxide to yield a fine white powder with an acid number of 160.

(B) Preparation of solution A 10% solution of the resin was prepared by the method described in Example I except that only 12 parts of sodium hydroxide were used. This solution was much higher in viscosity than the solution of Example I and somewhat higher in viscosity than the solution described in Example II.

(C) Application of resin to yarn One hundred (100) parts of this solution were diluted to 1000 parts with water and used to size a beam of 150 denier 40-filament viscose yarn on a regular rayon slasher. The sized yarn was slightly stiffer and harsher than the yarn sized in Examples I and II, but was superior to gelatinsized yarn. It wove satisfactorily and the fabric dyed uniformly.

EXAMPLE IV (A) Preparation of resin Eighty-seven and five-tenths (87.5) parts of methacrylic acid and 12.5 parts of methyl methacrylate were interpolymerized by heating in toluene in the presence of 1 part of benzoyl peroxide. A fine white powder was obt ined'having an acid number of 5'70.

"(8) Preparation of solution One hundred (100) parts .of the above resin were stirred into a solution containing 600 parts of water and 38 parts of sodium hydroxide.

Stearn was passed into the mixture until the tem- (C) Application of the resin to the yarn This resin was applied in the same manner as l the resin of Example III. A gray fabric was obtained which was exceptionally soft and pleasing to the touch.

Exnsru: V

The solution described in Example I, Part B, was diluted to a concentration of 1% and used to size a beam of 32 ends of 150 denier 40-fllament viscose rayon to be used as the pile thread in a velvet fabric having a pure silk back. It is especially important in weaving such fabrics that the viscose yarn be soft and flexible so that it will bend closely around the silk warp threads and be firmly held as the pile in the finished fabric. The yarns sized with this solution were particularly well suited in this respect. After the goods were scoured to remove the gum from the silk they were dyed, and it was noted that the color was uniform over the entire surface, free of the spots and streaks which frequently occur when gelatin-sized filling thread is used.

Exauru: VI

The solution described in Example I, Part B, was diluted to a concentration of 0.75% and used in accordance with Example V. No weaving dif ficulties were encountered and a gray fabric was obtained which was slightly softer than that obtained in Example V. This fabric dyed very uniformly.

Exmru: VII

Sixty-five (65) parts of propyl methacrylate and 35 parts of methacrylic acid were heated in toluene with 1 part of benzoyl peroxide to give a fine white powder having an acid number of 228. One hundred (100) parts of this resin were stirred into a solution of 16 parts of sodium hydroxide and 600 parts of water, and steam bubbled in until solution was complete. This solution was diluted with 10 parts of water to 1 part of solution to give a concentration of 1% and used to size a beam of 150 denier 40-filament viscose rayon yarn. This yarn wove with very little fiufling and gave a soft fabric which was readily desized and which dyed uniformly.

EXAMPLE IX The solution described in Example I, Part B, was diluted to a concentration of 2% by adding 5 parts of water to 1 part of the original solution. This solution was heated to 110 F. and used to size a skein of acetate rayon. The rayon wet out readily in this solution and after centrifuging and drying possessed a soft finish. The filaments were satisfactorily coated and the breaking test and thumb nail test indicated that the yarn would'be satisfactory, when used as a warp, for weaving into fabric.

The method of preparing the interpolymers of this invention has been illustrated in the above examples with special reference to toluene as the solvent. However, the method is not limited to the use of toluene for in its place, other solvents may be used such as benzene, xylene, 'ether, methyl alcohol, ethyl alcohol, etc., or the solvent may be dispensed with entirely and a granulated product rather than a powder be made by mixing the methacrylic acid and alkyl methacrylate in the required amounts in the presence of a catalyst, and then granulating the interpolymer as it is being formed by the use of known granulating agents. In this manner the interpolymer is produced in the form of fine granules which is a convenient form for handling and shipping.-

They can be readily dissolved in caustic to give the desired solution 'for sizing.

The preparation of the granulated interpolymer is illustrated by the following example:

EXAMPLE X meric methacrylic acid and 108 grams of benzoylperoxide was added. The stirring device was again started and indirect heating was applied until a, temperature of C. was reached in the charge, following which cooling was applied as a necessary to maintain this internal temperature. Approximately forty minutes was required from addition of the monomer until polymerization was completed. Polymerization is essentially completed at the time refluxing is no longer obtained at 90 C. and is also evidenced by a drop in the intemal temperature. The polymer appears as very fine, solid granules which are dispersed in the aqueous phase as long as stirring is continued and settled when stirring its stopped. If desired, the polymer slurry may be filtered or centrifuged and dried to obtain the methacrylic acid-methyl methacrylate interpolymer in a dry, solid form, or the interpolymer may be converted to the water-soluble sodium salt by transferring the entire polymer slurry to a vessel containing a stirred solution of 8 pounds of sodium hydroxide and 10.5 gallons of water and stirring until the interpolymer is completely dissolved. A viscous aqueous solution of the sodium salt with a pH between 8 and 9 is obtained.

Also, in place of the alkali solution of the interpolymers, the corresponding alkali salts of the inter-polymers may be isolated from their solution in alkali, by, for example, precipitation with methyl alcohol. Such salts can be conveniently shipped and stored and can be dissolved directly in water to form the size solution.

These examples are not intended to cover all the possible methods of preparation and application of these materials nor all the types of fabrics for which they can be used. To anyone skilled in the art of textile sizing it will be obvious that a great many other variations are possible in these materials and in the methods of application.

The sizing agents disclosed in this invention may be used for sizing viscose rayon, acetate rayon, or cotton. It is best suited for rayon sizing. Any foaming which may occur can be eliminated by adding anti-foaming agents. Concentrations of about 1% are most generally satisfactory but for acetate sizing concentrations as high as 4 or 5% may be desirable, whereas in some lower count viscose rayon fabrics, as low as 0.5% may sometimes be sufficient.

All of these sizing agents contain methacrylic acid as one component used in making the interpolymer. The alkyl methacrylate or ester constituent may be varied within wide limits. The preferred ester is methyl methacrylate, but esters of other short chain alcohols such as ethyl, propyl, butyl or isobutyl alcohols are satisfactory.

This invention is characterized principally by the following advantages. Less of my composition is required to give adequate protection to the yarn as compared with prior art compositions, and it yields an exceptionally soft, flexible gray fabric without the aid of softening agents.

As the salts of my interpolymers are readily soluble in hot water, very little scouring action is required to remove them from the gray fabric. In fact, it is possible to put the gray goods directly into the dye bath without previous scouring, although this is not always practicable since gray goods are often contaminated with grease or oils from the loom. Indeed, the sodium salts of these polycarboxylic acids are soaps which :act as wetting agents and facilitate the removal of dirt and grease. In many cases they are useful as dye assistants.

The compositions of this invention are capable of reproduction from batch to batch, they can be stored indefinitely without harmful results, are immune to bacterial growth, and are stable to acids or alkalis.

The above description is for purposes of illustration only, it being understood that all appar ent variations within the spirit of my invention.

are to be included in the scope thereof as defined in the appended claims.

I claim: 1

l. Cellulosic textile materials sized with an aqueous liquid containing from about 0.5 to about 5% by weight of a water-soluble salt of an interpolymer consisting of methacrylic acid and an alkyl methacrylate having not more than four carbon atoms in the alkyl group.

2. Cellulosic textile materials sized with an aqueous liquid containing from about 0.5 to about 5% by weight of a water-soluble salt of an interpolymer consisting of methacrylic acid and methyl methacrylate.

3. A process for sizing ceilulosic textile materials which comprises impregnating said materials with an aqueous liquid containing from about 0.5 to about 5% by weight of a water-s01- uble salt of an interpolymer consisting of methacryiic acid and an alkyl methacrylate having not more than four carbon atoms in the alkyl group.

4. A process for sizing ceilulosic textile materials which comprises impregnating said materials with an aqueous liquid containingfrom about 0.5 to about 5% by weight of a water-soluble salt of an interpolymer consisting of methacrylic acid and methyl methacrylate.

MERLIN M'ARTIN BRUBAKER. 

